Forty-eight children will be followed in a continuing five-year longitudinal study of the interrelationships between sebaceous gland developmnt, acne, androgens, and pubertal development. In each subject, forehead sebum samples are collected four times yearly and the relative composition of lipids analyzed by thin-layer chromatography. Physical examinations are done twice yearly and include height, weight and other signs of pubertal maturation. In 39 subjects, 24-hour urine specimens are collected twice yearly and analyzed for testosterone and total 17-ketosteroids. In 15 subjects, 3-hour sebum production tests are performed. In addition to providing possible markers of early pubertal maturation, normal and abnormal, by skin sebaceous measurements, the results of these studies may serve to identify early, children at risk for the development of significant acne and thereby consideration for earlier therapeutic intervention.